The Frankish World
The one western kingdom that did claim to have replaced the empire, and the thing it turned into. A Frankish king was crowned emperor in Rome in 800 and the title outlived his dynasty, his kingdom and the division of his inheritance by a thousand years.
The line below is a time axis. Position on it is date, so concurrency is visible: concurrent polities sit side by side rather than in sequence.
4 sourced edges run between this region and another, to Roman Empire, Kingdom of Sicily and Lombard Kingdom. Those are not drawn on this line — a thread that crossed regions would assert a sequence nobody cited — but they are on each polity’s own page.